bluto951

but it is working...after a quick run before I got home...ran out 15minutes later to mess with the stereo I just installed and both fans kicked on in accessory...resistor looks clean and no physical signs of failure on the relay...could the relay be bad w/out showing the normal physical signs of failure?

Anything else to check?

I've been referring to clarks directions on checking the cooling fan as well but none seem to apply here..

Lastly..I think I am going to double check the thermo fan switch out tomorrow...if I remove the air box I should get pretty good access right?

Thanks!

lee101315

Most of the time, yes. However, I would recommend checking the fuses and then feeding two jumper wires directly to the fan from the battery to make sure thats your problem... It could be many other things too.

bluto951

bah...so I ran out to the car after a quick run to mess with the stereo I just installed turned it to accessory and the both fans kicked on...so it is working...wondering if the mechanic but in a high speed fan switch instead of a low speed one when he replaced the radiator.

oh and the fan's fuse was blown two weeks ago ...the resistor looks clean and the relay looks fine as well...back to the drawing board..

bearone

the switches are hi or low temp, relays/resistors/magic gives the two speeds on some, i only have hi speed when they come on as water temp gets up or if a/c is on.

87951
95sl320 dd

bluto951

thanks with the high when do your fans usually kick in on your guage?

bearone

if you mean voltmeter, yes i see it and can hear them.

87951
95sl320 dd

cruise98

The fans are controlled by the relay which receives open/closed circuits from the thermo switch, refrigerant temp switch, and the a/c control switch.

You should always have power available to the relay, so the fans can run at any time. If the fans are not running, ignition switch off, a/c switch off, and you turn the ignition switch to acc and they starting running, something is wrong.

First thing to do is check for voltage...

Turn off the ignition and remove the cooling fan relay.

1. Check for voltage at positions 30 M1 and 30 M2, you should get 12v + at both positions. If no voltage, check the wiring from the battery, the connections to the fuse panel, and the fuse panel itself. You will have to pull the fuse panel up. Disconnect the battery before messing with the fuse panel.

2. Next for continuity between ground and the temp switch position on the fuse panel. If you have continuity, the thermo switch is calling for fan operation. If the car is cold, the thermo switch is bad.

3. Fabricate a jumper wire with flat blade connectors on each end, and a 20a fuse in the middle.

4. Connect M1 30 to M1, the drivers fan should run at high speed
5. Next, jumper between M1 30 and M2, the passenger fan should run at high speed
If both of these are not true, chase down the wiring, or check the fan motor.

6. Next jumper between M2 30 and V1, the drivers fan should run at low speed
7. Next jumper between M2 30 and V2, the passenger fan should run at low speed
If you do not get low speed operation, the resistors are probably bad, but it could be wiring.

If these tests all check out OK, the relay is bad.

Happy hunting.

bluto951

Thanks for all the info...but regarding this quote...couldn't it be possible if the car was still warm that when I switched to accessory for them to come back on to bring the overall temp down?

Looks like I'll be doing some trouble shooting next weekend.

Thanks again

bluto951

Actually I was referring to the temp guage..where is the needle when the fans kick in?

fbgh2o

With respect to the relay - absolutely I have a bad one and it looks no different that the good one.

The answer to your last question depends on the type of themoswitch you have.

IIRC, with the stock switch - low speed fans come on @ 92C; and the high speed fans @ 102C. However there are others that allow them you come on @ 85C and 93C respectively (which I have) and maybe even some that come on lower than that.

bluto951

I am pretty sure that when I had the radiator replaced the mechanic swapped in a high temp switch for the lowspeed I had in the old radiator...need to confirm that. But that should not prevent the low speed fans from coming on...which really seems to be at the center of the issue right now..

I might just get the relay and be done with it..

bluto951

I am pretty sure that when I had the radiator replaced the mechanic swapped in a high temp switch for the lowspeed I had in the old radiator...need to confirm that. But that should not prevent the low speed fans from coming on...which really seems to be at the center of the issue right now..

I might just replace relay and be done with it..

cruise98

You should always have battery power available to the relay at two positions regardless of the ignition switch position. If the fans run in the accessory position, but not with the switch off, it is probably either the relay itself or something to do with the a/c control unit as that is the only device that will provide a ground with the switch on. Be sure the snowflake switch is off when checking this. If it is off, the fans should not run in the accessory position unless the car is hot of course.

The radiator thermo switch and the refigerant temp switch will each run the fans at high speed with the switch on or off. If your fans operate correctly with the jumper connections I listed before, the relay is most likely the problem.

fbgh2o

I am inclined to agree that it is either the relay or the driver's side fan motor itself...

bearone

not sure, i can't watch both. next time i'll watch the temp gage.

if the temp is still up and you turn the key on, the fan's will run, mine do.

87951
95sl320 dd